CA2915399A1 - Libs measuring tube - Google Patents
Libs measuring tube Download PDFInfo
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- CA2915399A1 CA2915399A1 CA2915399A CA2915399A CA2915399A1 CA 2915399 A1 CA2915399 A1 CA 2915399A1 CA 2915399 A CA2915399 A CA 2915399A CA 2915399 A CA2915399 A CA 2915399A CA 2915399 A1 CA2915399 A1 CA 2915399A1
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- measuring tube
- tube
- analysate
- salt
- libs
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- 235000002639 sodium chloride Nutrition 0.000 claims abstract description 99
- 150000003839 salts Chemical class 0.000 claims abstract description 74
- 238000002536 laser-induced breakdown spectroscopy Methods 0.000 claims abstract description 56
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 25
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 25
- 239000011777 magnesium Substances 0.000 claims abstract description 25
- 238000012545 processing Methods 0.000 claims abstract description 25
- 239000011780 sodium chloride Substances 0.000 claims abstract description 25
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 24
- 239000013067 intermediate product Substances 0.000 claims abstract description 24
- 238000005259 measurement Methods 0.000 claims abstract description 22
- 239000013590 bulk material Substances 0.000 claims abstract description 21
- 238000000295 emission spectrum Methods 0.000 claims abstract description 15
- 230000005855 radiation Effects 0.000 claims abstract description 14
- 230000008878 coupling Effects 0.000 claims abstract description 7
- 238000010168 coupling process Methods 0.000 claims abstract description 7
- 238000005859 coupling reaction Methods 0.000 claims abstract description 7
- 238000004458 analytical method Methods 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 33
- 230000008569 process Effects 0.000 claims description 31
- 229910052700 potassium Inorganic materials 0.000 claims description 25
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 24
- 239000011591 potassium Substances 0.000 claims description 24
- 239000011261 inert gas Substances 0.000 claims description 22
- 229910052717 sulfur Inorganic materials 0.000 claims description 15
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 14
- 239000011593 sulfur Substances 0.000 claims description 14
- 238000007790 scraping Methods 0.000 claims description 12
- 230000003287 optical effect Effects 0.000 claims description 10
- 238000007654 immersion Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 5
- 230000003595 spectral effect Effects 0.000 claims description 5
- 238000001228 spectrum Methods 0.000 claims description 5
- 229910052729 chemical element Inorganic materials 0.000 claims description 4
- 239000006185 dispersion Substances 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- 239000008279 sol Substances 0.000 claims description 4
- 239000000499 gel Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 abstract description 23
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 abstract 1
- 238000007598 dipping method Methods 0.000 abstract 1
- 235000001055 magnesium Nutrition 0.000 abstract 1
- 229940072033 potash Drugs 0.000 abstract 1
- 235000015320 potassium carbonate Nutrition 0.000 abstract 1
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 abstract 1
- 230000007246 mechanism Effects 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 8
- 238000004886 process control Methods 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 239000000523 sample Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000002679 ablation Methods 0.000 description 4
- 235000013619 trace mineral Nutrition 0.000 description 4
- 239000011573 trace mineral Substances 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 238000001533 laser emission spectroscopy Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000010223 real-time analysis Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000013528 artificial neural network Methods 0.000 description 1
- 238000001636 atomic emission spectroscopy Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000013142 basic testing Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- 238000010921 in-depth analysis Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000001499 laser induced fluorescence spectroscopy Methods 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 238000012417 linear regression Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000000144 pharmacologic effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000000513 principal component analysis Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- -1 raw Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
- G01N21/718—Laser microanalysis, i.e. with formation of sample plasma
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0291—Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/443—Emission spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/85—Investigating moving fluids or granular solids
- G01N21/8507—Probe photometers, i.e. with optical measuring part dipped into fluid sample
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
- G02B7/023—Mountings, adjusting means, or light-tight connections, for optical elements for lenses permitting adjustment
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/15—Preventing contamination of the components of the optical system or obstruction of the light path
- G01N2021/152—Scraping; Brushing; Moving band
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/85—Investigating moving fluids or granular solids
- G01N2021/8592—Grain or other flowing solid samples
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
- G01N2201/06113—Coherent sources; lasers
Abstract
The invention relates to a special LIBS measurement tube focusing unit, referred to simply as LIBS measurement tube, for vertically dipping into a material to be analyzed, which material is moved in a horizontal flow, characterized in that the measurement tube extends vertically and is internally hollow and open at least at the bottom end, such that a bottom edge is formed at the bottom end, the measurement tube has an inlet for coupling in a laser beam and an outlet for coupling out an emission spectrum at the upper end, the measurement tube is constructed in such a way that, in the measurement tube, the laser beam is focused at the material to be analyzed, specifically bulk material, in particular raw, intermediate, and end products from the processing of potash, magnesium, rock salt, or evaporated salt, but without additional scattering and deflection occurring, such that a plasma of the material to be analyzed is produced within the measurement tube by the laser radiation and the emission spectrum of the material to be analyzed reaches the outlet for outcoupling through the interior of the measurement tube, and scrapers (1, 2) lie on the inner and outer focusing tube wall annularly, preferably at the same vertical height on the focusing tube (3), which scrapers are arranged in such a way that the scrapers can be moved vertically in relation to the focusing tube (3), such that material to be analyzed that adheres to the focusing tube (3) on the inside and outside in the lower region can be scraped off by a relative motion of the focusing tube (3) in relation to the scrapers (1, 2).
Description
LIBS Measuring Tube The invention relates to a special LIBS measuring tube allowing a continuous online analysis, especially of elements in the VUV (vacuum UV) range, preferably sulfur, to an online LIBS analysis unit comprising same, to its application for the qualitative and/or quantitative online determination of individual or multiple chemical elements of an analysate, especially loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, which is moved in a horizontal flow past the measuring tube, and to a relevant process.
Laser-induced plasma spectroscopy (LIPS), also referred to as laser-induced breakdown spectroscopy (LIBS), constitutes a quick non-contact measuring method for the element analysis of solid, liquid or gaseous substances under normal ambient conditions without special preparation of samples.
The abbreviation "LIBS" is used below. LIBS is a form of atomic emission spectroscopy using a high-energy laser pulse as the excitation source. The laser is focused upon a analysate. If the laser energy is above a certain critical value, the material evaporates, typically in the nano to micro gram range. Thanks to further light absorption of the high-energy laser pulse, the resulting microwave heats up to high temperatures of typically more than 10,000 C, and a microplasm is formed at the sample surface, i.e. a gaseous mixture of ions, electrons and excited neutral atoms is formed. In the plasma, the excited atoms and ions radiate a characteristic spectrum also called the "fingerprint emission spectrum" which allows - by means of a quick spectroscopic analysis - not only a qualitative, but, depending on the evaluation system, also a quantitative analysis of the element composition of the analysate. In principle, the LIBS method allows the detection of all elements of the periodic table as long as their element-specific emission spectrum is known.
In principle, the LIBS process is limited only by the laser performance, interferences such as peak absorption and/or peak superposition and by the sensitivity and the wavelength range of the detector. In practice, the detection limits depend on the plasma excitation temperature, the light collection window and the line width of the observed transition.
In data acquisition, one typically waits until a thermodynamic equilibrium is established in the plasma and the plasma temperatures are in the range of 5,000 to 20,000 C. At the high temperatures in the initial phase of the plasma, the evaporated material dissociates into excited species of ions and atoms. At that time, the plasma emits a continuum of radiation that cannot be meaningfully analyzed.
Pa Within a very short period of time, the plasma expands at supersonic speed and cools. At that point in time, the characteristic atomic emission lines of the individual elements can be observed and analyzed. The time difference between the emission of continuous radiation and the characteristic radiation is in the range of 10 ps, such that the detector has to be clocked accordingly.
A typical LIBS system comprises an Nd:YAG solid laser and a spectrometer with a wide spectral range and high sensitivity, fast response and a time-controlled detector. The LIBS system is connected to a computer that can process and evaluate the recorded measuring data.
The Nd:YAG laser generates pulsed laser radiation with a wavelength of 1,064 nm, in which pulse durations in the range of 10 ns power densities can be reached, and these can exceed 1 GW/cm2 at the focal point. Other lasers that can be used for LIBS applications are Excimer lasers which generate energy in the visible range and in the UV range of the spectrum.
In principle, the spectrometer used in the analysis is designed either with a monochromator (with scanning mode) or a polychromator (without scanning mode) and a photomultiplier or CCD detector. Frequently used polychromators are of the EcheIle type or Paschen-Runge arrangement. The monochromator of the Czerny-Turner detector type can also be used to disperse the radiation on a CCD, resulting in a polychromator. The most frequently used type in LIBS applications is the polychromator spectrometer, since it allows the simultaneous recording of the entire relevant wavelength range. The various spectrometer arrangements available can serve to summarize measurements - similarly as with an IPC spectrometer - from an overall wavelength range of about 170 nm (deep UV) to about 1100 nm (near IR),
Laser-induced plasma spectroscopy (LIPS), also referred to as laser-induced breakdown spectroscopy (LIBS), constitutes a quick non-contact measuring method for the element analysis of solid, liquid or gaseous substances under normal ambient conditions without special preparation of samples.
The abbreviation "LIBS" is used below. LIBS is a form of atomic emission spectroscopy using a high-energy laser pulse as the excitation source. The laser is focused upon a analysate. If the laser energy is above a certain critical value, the material evaporates, typically in the nano to micro gram range. Thanks to further light absorption of the high-energy laser pulse, the resulting microwave heats up to high temperatures of typically more than 10,000 C, and a microplasm is formed at the sample surface, i.e. a gaseous mixture of ions, electrons and excited neutral atoms is formed. In the plasma, the excited atoms and ions radiate a characteristic spectrum also called the "fingerprint emission spectrum" which allows - by means of a quick spectroscopic analysis - not only a qualitative, but, depending on the evaluation system, also a quantitative analysis of the element composition of the analysate. In principle, the LIBS method allows the detection of all elements of the periodic table as long as their element-specific emission spectrum is known.
In principle, the LIBS process is limited only by the laser performance, interferences such as peak absorption and/or peak superposition and by the sensitivity and the wavelength range of the detector. In practice, the detection limits depend on the plasma excitation temperature, the light collection window and the line width of the observed transition.
In data acquisition, one typically waits until a thermodynamic equilibrium is established in the plasma and the plasma temperatures are in the range of 5,000 to 20,000 C. At the high temperatures in the initial phase of the plasma, the evaporated material dissociates into excited species of ions and atoms. At that time, the plasma emits a continuum of radiation that cannot be meaningfully analyzed.
Pa Within a very short period of time, the plasma expands at supersonic speed and cools. At that point in time, the characteristic atomic emission lines of the individual elements can be observed and analyzed. The time difference between the emission of continuous radiation and the characteristic radiation is in the range of 10 ps, such that the detector has to be clocked accordingly.
A typical LIBS system comprises an Nd:YAG solid laser and a spectrometer with a wide spectral range and high sensitivity, fast response and a time-controlled detector. The LIBS system is connected to a computer that can process and evaluate the recorded measuring data.
The Nd:YAG laser generates pulsed laser radiation with a wavelength of 1,064 nm, in which pulse durations in the range of 10 ns power densities can be reached, and these can exceed 1 GW/cm2 at the focal point. Other lasers that can be used for LIBS applications are Excimer lasers which generate energy in the visible range and in the UV range of the spectrum.
In principle, the spectrometer used in the analysis is designed either with a monochromator (with scanning mode) or a polychromator (without scanning mode) and a photomultiplier or CCD detector. Frequently used polychromators are of the EcheIle type or Paschen-Runge arrangement. The monochromator of the Czerny-Turner detector type can also be used to disperse the radiation on a CCD, resulting in a polychromator. The most frequently used type in LIBS applications is the polychromator spectrometer, since it allows the simultaneous recording of the entire relevant wavelength range. The various spectrometer arrangements available can serve to summarize measurements - similarly as with an IPC spectrometer - from an overall wavelength range of about 170 nm (deep UV) to about 1100 nm (near IR),
2 which corresponds to the approximate sensitivity range of a CCD detector. As a rule, considering the size of the LIBS system, instead of using an IPC spectrometer, other spectrometer types are commonly used which are sensitive only to a defined wavelength range and do not cover the entire wavelength range named above.
All elements have emission lines in this wavelength range. Depending on the quality of the measuring device, adjacent spectral emission lines can also be resolved. By reducing interferences, selectivity can be increased.
In addition to the spectrometer and the detector, a delay generator is used which delays the detector's response time, allowing a temporal profile of the spectrum to be resolved.
Since only very small amounts of the analysate are consumed during LIBS
is measuring, the process is regarded as non-destructive or minimally destructive. With the repeated discharge of the laser upon the same position in the material, depth profiles of the examined material can be generated where surface contamination of the material can be removed prior to the actual measuring.
The LIBS process is a purely optical process, and only optical access to the analysate is required. When fibre optics are used, the radiation source and the analysis unit can be spatially separated from the analysate.
The advantages of the LIBS process are that it is fast and non-contact, that there is little sample ablation, and that it requires practically no preparation of samples.
Multiple linear regression and principal component analysis (PCA LIBS), PCA
LIBS
in a neural network or calibration-free processes (CF LIBS) are often used as evaluation methods.
The implementation of laser emission spectroscopy with moving objects is known per se. DE-A-10 2008 032 532 describes a process and an apparatus for preparatory laser material ablation allowing a sample preparation by means of material ablation before the actual laser emission spectroscopy.
In the industry, LIBS is now often used in the analysis of recycling metal.
All elements have emission lines in this wavelength range. Depending on the quality of the measuring device, adjacent spectral emission lines can also be resolved. By reducing interferences, selectivity can be increased.
In addition to the spectrometer and the detector, a delay generator is used which delays the detector's response time, allowing a temporal profile of the spectrum to be resolved.
Since only very small amounts of the analysate are consumed during LIBS
is measuring, the process is regarded as non-destructive or minimally destructive. With the repeated discharge of the laser upon the same position in the material, depth profiles of the examined material can be generated where surface contamination of the material can be removed prior to the actual measuring.
The LIBS process is a purely optical process, and only optical access to the analysate is required. When fibre optics are used, the radiation source and the analysis unit can be spatially separated from the analysate.
The advantages of the LIBS process are that it is fast and non-contact, that there is little sample ablation, and that it requires practically no preparation of samples.
Multiple linear regression and principal component analysis (PCA LIBS), PCA
LIBS
in a neural network or calibration-free processes (CF LIBS) are often used as evaluation methods.
The implementation of laser emission spectroscopy with moving objects is known per se. DE-A-10 2008 032 532 describes a process and an apparatus for preparatory laser material ablation allowing a sample preparation by means of material ablation before the actual laser emission spectroscopy.
In the industry, LIBS is now often used in the analysis of recycling metal.
3 In the production of highly purified salt (NaCI of pharmaceutical quality, i.e. according to the European Pharmacopoeia), the sulfate content is one of the most important quality parameters. According to it, the threshold value is at 220 ppm sulfate in pharmacological quality salt.
The sulfate content, for example, is determined turbidimetrically. About one hour passes between sampling and the corresponding laboratory reading, which means that when the threshold value for sulfate is exceeded, reaction cannot be fast enough. When an even lower threshold value is imposed internally, the sampling cycle is typically increased from several hours to one hour until the sulfate content is below the internal threshold value again. The time delay between sampling and the availability of the reading is a disadvantage.
It is therefore the object of the present invention to provide an analytical process and an analytical mechanism that allows the determination of the composition, and in particular the sulfur and sulfate content, under an inert gas atmosphere, in particular examining the raw, intermediate and end products from the processing of potassium, magnesium, rock salt and evaporated salt, for example of highly purified salt, with a shorter time delay. Preferably, an online real-time analysis is to be possible. Such a simple analysis is to be possible for a analysate, especially in a loose bulk material, and in particular in raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt.
A simple analysis is to be possible for a analysate which is being moved in a horizontal stream such as a salt being moved at an even rate on a conveyor belt.
Another object of the present invention is to provide a mechanism which, in conjunction with an optical module suitable for LIBS measurements, can analyze the composition, in particular of raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, for example of highly purified salt, with a shorter time delay. Preferably, an online real-time analysis is to be possible. Such a simple analysis is to be possible for a analysate, especially in a loose bulk material, and in particular in raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, whereby the analysate is moved in a horizontal stream.
The sulfate content, for example, is determined turbidimetrically. About one hour passes between sampling and the corresponding laboratory reading, which means that when the threshold value for sulfate is exceeded, reaction cannot be fast enough. When an even lower threshold value is imposed internally, the sampling cycle is typically increased from several hours to one hour until the sulfate content is below the internal threshold value again. The time delay between sampling and the availability of the reading is a disadvantage.
It is therefore the object of the present invention to provide an analytical process and an analytical mechanism that allows the determination of the composition, and in particular the sulfur and sulfate content, under an inert gas atmosphere, in particular examining the raw, intermediate and end products from the processing of potassium, magnesium, rock salt and evaporated salt, for example of highly purified salt, with a shorter time delay. Preferably, an online real-time analysis is to be possible. Such a simple analysis is to be possible for a analysate, especially in a loose bulk material, and in particular in raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt.
A simple analysis is to be possible for a analysate which is being moved in a horizontal stream such as a salt being moved at an even rate on a conveyor belt.
Another object of the present invention is to provide a mechanism which, in conjunction with an optical module suitable for LIBS measurements, can analyze the composition, in particular of raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, for example of highly purified salt, with a shorter time delay. Preferably, an online real-time analysis is to be possible. Such a simple analysis is to be possible for a analysate, especially in a loose bulk material, and in particular in raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, whereby the analysate is moved in a horizontal stream.
4 The object of the invention is achieved by means of a special LIBS measuring tube focusing unit, hereinafter abbreviated as measuring tube, for the vertical immersion in an analysate that is moved in a horizontal stream, especially loose bulk material, and in particular the raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, characterized in that the measuring tube extends vertically, is hollow on the inside and is open at least at its lower end such that a bottom edge is formed at its bottom end, the measuring tube has at its top end an inlet for coupling a laser beam and an outlet for uncoupling an emission spectrum, the measuring tube is designed such that inside the measuring tube the laser beam is focused such that inside this measuring tube, without any additional scattering or deflection, the laser radiation generates a plasma of the analysate, and the emission spectrum of the analysate passes through the inside of the measuring tube to be uncoupled at the outlet, on the inner and outer wall of the focus tube, scraper rings are provided at the focus tube, preferably at the same vertical height, which can be moved up and down on the focus tube, such that a build-up of analysate in the bottom section inside and outside the focus ring can be scraped by moving the focus tube relative to the scraping rings.
Preferably, the analysate consists of raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt. The salt can be obtained by chemical conversion.
Preferably, the measuring tube is adapted to the online LIBS sulfur or sulfate analysis of raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt.
The object is also achieved by an online analysis unit consisting of an LIBS measuring tube as described above,
Preferably, the analysate consists of raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt. The salt can be obtained by chemical conversion.
Preferably, the measuring tube is adapted to the online LIBS sulfur or sulfate analysis of raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt.
The object is also achieved by an online analysis unit consisting of an LIBS measuring tube as described above,
5 a laser beam source, a spectrometer unit for the detection of the LIBS emission spectrum, with analysis optics for the spectral range of 170-590 nm and possibly for detection in the IR range, optical components for coupling the laser beam in the measuring tube (part of the focusing optics), an electronic control system for operating the laser beam source and the detector unit and for data acquisition, a preferably pneumatic drive unit for the automatic movement of the focus tube in relation to the scraper rings, an arrangement for feeding inert gas into the measuring tube which allows the detection of elements emitting in the VUV range, preferably of sulfur.
The object is also achieved by using such a measuring tube or such an online LIBS
analysis unit for the qualitative and/or quantitative online determination of individual or multiple chemical elements of a analysate, especially loose bulk material, and in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt which is moved in a horizontal stream past the measuring tube.
The object is also achieved by a process for the qualitative and/or quantitative online zo determination of individual or multiple chemical elements of a analysate, especially loose bulk material, and in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt which is moved in a horizontal stream past the measuring tube, with an online LIBS analysis unit as described above, where the LIBS measuring tube is immersed vertically into an analysate and which is moved in a horizontal stream, especially loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, where a laser beam is generated by a laser beam source and focused upon the analysate in the measuring tube, such that a plasma is generated by the laser radiation of the analysate, especially loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, is formed inside the measuring tube, and the emission spectrum of the analysate passes to the outlet to be uncoupled, then to the detector unit where the measuring process takes place.
The object is also achieved by using such a measuring tube or such an online LIBS
analysis unit for the qualitative and/or quantitative online determination of individual or multiple chemical elements of a analysate, especially loose bulk material, and in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt which is moved in a horizontal stream past the measuring tube.
The object is also achieved by a process for the qualitative and/or quantitative online zo determination of individual or multiple chemical elements of a analysate, especially loose bulk material, and in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt which is moved in a horizontal stream past the measuring tube, with an online LIBS analysis unit as described above, where the LIBS measuring tube is immersed vertically into an analysate and which is moved in a horizontal stream, especially loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, where a laser beam is generated by a laser beam source and focused upon the analysate in the measuring tube, such that a plasma is generated by the laser radiation of the analysate, especially loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, is formed inside the measuring tube, and the emission spectrum of the analysate passes to the outlet to be uncoupled, then to the detector unit where the measuring process takes place.
6 It was found that with LIBS it is possible to determine main and/or trace elements in salts, in particular pharmaceutical salt and potassium salt, if a measuring tube according to the invention is used, whereby the salts are typically moved in a horizontal stream on a conveyor belt.
The LIBS measuring tube and the online LIBS analysis unit according to the invention allow the determination of main and/or trace elements in salts, for example in potassium salt and pharmaceutical salt, with a high degree of accuracy and reliability in online real-time mode. The online analysis of main, minor and trace elements in raw, intermediate and end products from the processing of potassium lo salt and rock salt industry is possible. The online determination of elements emitting in the UV range such as sulfur under an inert gas atmosphere is also possible.
In particular, K, Na, Ca, Mg and S can be analyzed in salts. Typically, S must also be determined under an inert gas atmosphere (for example also for C and P).
Preferably the online determination of sulfur in the trace element range by means of LIBS must be carried out with sufficient accuracy in the UV or VUV wavelength range. Due to the absorption of element-specific wavelengths by air, this determination must preferably be conducted under an inert gas atmosphere.
According to the invention, nitrogen and argon are the preferred inert gases.
Thus, by determining sulfur, the sulfate content of the salt, for example of pharmaceutical salt, is possible.
The process according to the invention allows a quasi real-time process control and process adaptation or process optimization in case of deviating threshold values.
The measuring system can be installed for specific applications and optionally using an inert gas, for example above a conveyor belt or turntable. In this case, the analysis is continuous with moving sample material. The analysis results are available online and can thus be transferred to the relevant process control centre.
An LIBS measuring tube is described which is meant to be vertically immersed into an analysate in a horizontally moving stream. According to the invention, the term "vertical" includes deviations from the vertical by 44 , preferably 22 , in particular 110, and especially also 5 .
According to the invention, the term "horizontal includes deviations from the horizontal by 44 , preferably 22 , in particular 110, and especially also .
The LIBS measuring tube and the online LIBS analysis unit according to the invention allow the determination of main and/or trace elements in salts, for example in potassium salt and pharmaceutical salt, with a high degree of accuracy and reliability in online real-time mode. The online analysis of main, minor and trace elements in raw, intermediate and end products from the processing of potassium lo salt and rock salt industry is possible. The online determination of elements emitting in the UV range such as sulfur under an inert gas atmosphere is also possible.
In particular, K, Na, Ca, Mg and S can be analyzed in salts. Typically, S must also be determined under an inert gas atmosphere (for example also for C and P).
Preferably the online determination of sulfur in the trace element range by means of LIBS must be carried out with sufficient accuracy in the UV or VUV wavelength range. Due to the absorption of element-specific wavelengths by air, this determination must preferably be conducted under an inert gas atmosphere.
According to the invention, nitrogen and argon are the preferred inert gases.
Thus, by determining sulfur, the sulfate content of the salt, for example of pharmaceutical salt, is possible.
The process according to the invention allows a quasi real-time process control and process adaptation or process optimization in case of deviating threshold values.
The measuring system can be installed for specific applications and optionally using an inert gas, for example above a conveyor belt or turntable. In this case, the analysis is continuous with moving sample material. The analysis results are available online and can thus be transferred to the relevant process control centre.
An LIBS measuring tube is described which is meant to be vertically immersed into an analysate in a horizontally moving stream. According to the invention, the term "vertical" includes deviations from the vertical by 44 , preferably 22 , in particular 110, and especially also 5 .
According to the invention, the term "horizontal includes deviations from the horizontal by 44 , preferably 22 , in particular 110, and especially also .
7 The arrangement of the measuring tube and the analysate and moved in the stream is such that there is an even stream of the analysate, and it is possible to immerse the bottom part of the measuring tube into the stream of the analysate to conduct an analysis of the analysate at the immersion site, such as in the VUV range, as in the case of sulfur.
Particularly preferable is the vertical immersion of the measuring tube in a horizontal stream of the analysate, i.e. at an angle of 900 20 , preferably of 100, and in particular of 5 .
The measuring tube extends vertically in the above sense. It has an extension in the vertical direction to allow a distance between the inlet for coupling the laser beam and the outlet for uncoupling the emission spectrum and the sample surface, i.e. the surface of the analysate. Preferably the distance between the last optical system of is the measuring system and the mean material surface is at least 50 mm, preferably at least 100 mm, and in particular at least 200 mm. Typically, the distance between the last optical system of the measuring system and the mean material surface can be approximately 250 cm.
The focus tube can have any suitable form. Typically it is designed in tubular form with any cross section. Preferred is an elliptical or in particular a circular cross section of the focus tube.
"At the top end" means an area above the middle of the measuring tube (in vertical direction), preferably in the top third of the measuring tube, in particular in the top quarter of the measuring tube. It is especially preferred to have the inlet as close as possible to the upper end of the measuring tube.
The term "in the bottom area", used according to the invention for scraping the focus tube, refers to an area below the middle of the measuring tube (in vertical direction), preferably the bottom third, in particular the bottom quarter of the measuring tube.
Preferably, for measuring elements under an inert gas atmosphere, plasma is generated and the emission spectrum is created inside the measuring tube when the bottom end of the measuring tube is immersed in the analysate. To conduct the
Particularly preferable is the vertical immersion of the measuring tube in a horizontal stream of the analysate, i.e. at an angle of 900 20 , preferably of 100, and in particular of 5 .
The measuring tube extends vertically in the above sense. It has an extension in the vertical direction to allow a distance between the inlet for coupling the laser beam and the outlet for uncoupling the emission spectrum and the sample surface, i.e. the surface of the analysate. Preferably the distance between the last optical system of is the measuring system and the mean material surface is at least 50 mm, preferably at least 100 mm, and in particular at least 200 mm. Typically, the distance between the last optical system of the measuring system and the mean material surface can be approximately 250 cm.
The focus tube can have any suitable form. Typically it is designed in tubular form with any cross section. Preferred is an elliptical or in particular a circular cross section of the focus tube.
"At the top end" means an area above the middle of the measuring tube (in vertical direction), preferably in the top third of the measuring tube, in particular in the top quarter of the measuring tube. It is especially preferred to have the inlet as close as possible to the upper end of the measuring tube.
The term "in the bottom area", used according to the invention for scraping the focus tube, refers to an area below the middle of the measuring tube (in vertical direction), preferably the bottom third, in particular the bottom quarter of the measuring tube.
Preferably, for measuring elements under an inert gas atmosphere, plasma is generated and the emission spectrum is created inside the measuring tube when the bottom end of the measuring tube is immersed in the analysate. To conduct the
8 measuring, the laser beam is focused upon the analysate, i.e. on its surface.
For example, this can be done with the aid of an autofocus mechanism.
The analysate in a horizontal stream can preferably be in the form of a solid, gas, gel, sol, dispersion, liquid or a mixture thereof, especially as loose bulk material, in particular as a raw, intermediate and end product from the processing of potassium, magnesium, rock salt or evaporated salt. When the analysate is not itself capable of flowing, it is preferably presented in such a finely distributed form that it can lie on a conveyor belt and is pourable. A particularly preferable analysate is a solid, o especially a loose bulk material, in particular a raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt, especially when it consists of small particles. Preferably, the mean particle size is in the range between 0.5 and 10 mm, especially preferable between 2 and 4 mm, and in particular between 0.5 and 1 mm.
By immersing the measuring tube in the stream of the analysate, in particular loose bulk material, particularly raw, intermediate or end products from the processing of potassium, magnesium, rock salt or evaporated salt, especially in the case of loose bulk material with a moisture content of > 1%, the analysate can build up in the measuring tube. Typically this occurs where the measuring tube is immersed, i.e. at its bottom inner end. Since a wave of the material or the loose bulk material can form at the inflow side when the bottom part of the measuring tube is immersed in the analysate, a build-up/caking can be formed above the immersion position, especially with loose bulk material from the processing of potassium, magnesium, rock salt or evaporated salt with a moisture content of >1%.
The build-up can impair the LIBS analysis so much that the build-up/caking increases at the bottom inner end of the measuring tube, and the build-up greatly minimizes or even prevents the accuracy of the analysis of the freshly arriving analysate, especially of the loose bulk material, in particular of the raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt.
That is why the measuring tube has scraper rings at the inner and outer tube wall.
These are moved up and down in relation to the focus tube allowing the analysate
For example, this can be done with the aid of an autofocus mechanism.
The analysate in a horizontal stream can preferably be in the form of a solid, gas, gel, sol, dispersion, liquid or a mixture thereof, especially as loose bulk material, in particular as a raw, intermediate and end product from the processing of potassium, magnesium, rock salt or evaporated salt. When the analysate is not itself capable of flowing, it is preferably presented in such a finely distributed form that it can lie on a conveyor belt and is pourable. A particularly preferable analysate is a solid, o especially a loose bulk material, in particular a raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt, especially when it consists of small particles. Preferably, the mean particle size is in the range between 0.5 and 10 mm, especially preferable between 2 and 4 mm, and in particular between 0.5 and 1 mm.
By immersing the measuring tube in the stream of the analysate, in particular loose bulk material, particularly raw, intermediate or end products from the processing of potassium, magnesium, rock salt or evaporated salt, especially in the case of loose bulk material with a moisture content of > 1%, the analysate can build up in the measuring tube. Typically this occurs where the measuring tube is immersed, i.e. at its bottom inner end. Since a wave of the material or the loose bulk material can form at the inflow side when the bottom part of the measuring tube is immersed in the analysate, a build-up/caking can be formed above the immersion position, especially with loose bulk material from the processing of potassium, magnesium, rock salt or evaporated salt with a moisture content of >1%.
The build-up can impair the LIBS analysis so much that the build-up/caking increases at the bottom inner end of the measuring tube, and the build-up greatly minimizes or even prevents the accuracy of the analysis of the freshly arriving analysate, especially of the loose bulk material, in particular of the raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt.
That is why the measuring tube has scraper rings at the inner and outer tube wall.
These are moved up and down in relation to the focus tube allowing the analysate
9 that is building up outside on the measuring tube to be scraped off. This scraping occurs in particular in the area of the focus tube over which the scrapers are moved.
The invention allows the scrapers to move over a fixed tube. However, it is preferable to design the inner and outer scrapers as immovable and to move the focus tube up and down between the scrapers to accomplish the scraping in that fashion.
The scrapers form rings on the inner and outer focus tube wall. The vertical height of the scrapers can be selected In accordance with practical requirements. As the focus tube moves relative to the scrapers, the scrapers slide along the inner and outer wall of the focus tube in the bottom area, thus loosening particles of the analysate which build up on the measuring tube. To ensure the optimal functioning of the scrapers, they are preferably abutting the focus tube such that they do not dip into the horizontal stream of the analysate while measuring is being performed. On the other hand, the focus tube can also be cleaned while the scrapers are immersed due to the relative movement.
The particularly preferred movement of the focus tube relative to the fixed scrapers during the scraping process makes it possible to immerse the measuring tube into the continuing stream for another measurement, such that the salt composition on a conveyor belt is analyzed by the measuring position at time intervals.
During the measurement, the measuring tube sometimes penetrates the analysate so deeply that the bottom edge of the measuring tube is completely immersed in the analysate.
It has been proven to be advantageous to bevel the bottom end of the measuring tube such that the bottom edge of the measuring tube on the inflow side of the analysate stream immerses more deeply into the stream than on the oufflow side.
This prevents a stronger inflow of the analysate into the measuring tube and its rise inside the measuring tube.
The scraping movement can be driven in any suitable manner. Preferably, the measuring tube is provided with a pneumatic drive unit for the automatic relative movement of the focus tube relative to the scrapers.
It is also advantageous to provide a control unit to automate the scraping process.
The scraping movement can take place in regular variably adjustable time intervals during LIBS measurements in online mode.
Thus the LIBS measurement can be conducted in online mode while analysate building up on the measuring tube is scraped off, preferably automatically, by means of the movement of the focus tube relative to the scrapers.
According to a preferred embodiment, the measuring tube is provided with an inlet for receiving inert gas. This makes it possible to apply the LIBS analysis process under inert gas in online mode. This is necessary, for example, to determine sulfur in the UV range.
In these measurements it is preferred to fill the entire measuring tube with inert gas.
To prevent too much inert gas from escaping, the bottom edge of the measuring tube can be immersed completely in the analysate. However, as long as a sufficient stream of inert gas is provided, the bottom edge of the measuring tube can also lie partly or completely above the analysate as long as air or oxygen is prevented from entering in the area between the material surface and the top end of the measuring tube (inside).
Since the height of the poured analysate stream can vary, it is advantageous to provide an autofocus system in the online LIBS analysis unit that serves to adjust the measuring distance to the analysate.
The measuring tube according to the invention, the analysis unit according to the invention and the process according to the invention can be applied to any type of analysate: solid, gas, gel, sol, dispersion, liquid or mixtures thereof. A
preferred analysate is a salt, preferably a raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt.
In particular, the purpose of the process according to the invention is to determine the sulfur content of a salt in online mode under an inert gas atmosphere.
The LIBS analysis according to the invention can be performed as described in the introduction. Preferred designs of the measuring tube and the analysis unit are described below.
Preferably, the measuring system is provided with an automatic control and can signal the current state (such as standby, ready, measuring, error) to the superior process control system. In addition, self-testing is performed to ensure functional readiness.
The measuring system automatically performs measurements on moving material, for example on a conveyor belt.
During the examination of the material surface, the latter is subjected to laser radiation which induces the emission of plasma radiation. This is detected in an analysis optics and evaluated with the integrated signal electronics and control software.
The measuring system is designed to transmit the measuring results to a superior process control system.
Recalibration and test equipment monitoring is performed in predetermined time intervals.
All readings, test results and information regarding the system status are recorded.
The laser-based online measuring system and the continuous analysis allow a quasi real-time process control and process optimization.
Preferably, the analysis optics allows analysis in the spectral range from 170 to 590 nm and if need be also in the IR range. Using the LIBS process, the measuring system continuously examines the material, for example on a conveyor belt. The contents of the determined elements are available online to system users.
The measurement system consists of the following components: housing, laser source, optics including the measuring tube, autofocus system, electronic control system, software and protective devices.
The housing serves to accommodate all optical and electronic components and the media and user interfaces. Preferably, the housing, including cable entry, is protected against water jets, is dustproof, laser-proof and temperature-stabilized.
The measuring tube protects the optics against contamination and also allows the determination of elements under an inert gas atmosphere in the VUV range. The measuring tube is a part of the focusing optics and is flanged to the optic module which also includes the laser, optics and the spectrometer.
The laser used is a pulsed Nd:YAG laser source (laser class 4) with intermediate optical power of max. 30 W to excite the element-specific optical emissions.
An autofocus system serves to adjust the measuring distance, for example different layer thicknesses. It consists of distance sensors and traversing units which ensure the focusing of the laser beam upon the material surface.
The electronic control system serves to control the process.
The control software also serves to control the process, provides the connection to a process control system, to control and operate the measuring system, to evaluate the readings, calibration, recalibration, test equipment monitoring, interface to the process control computer, and also evaluates the log function, facility operation and remote maintenance.
In practice, preferably protective means are provided which protect against laser radiation and movable parts by means of an interlock circuit, safety locks, etc.
It is possible to guide the pulsed laser beam synchronous with movement with a preselected measuring point from the moved analysate such that successive laser pulses or laser bursts can be applied several times in a row upon the same sample point. This allows on the one hand an in-depth analysis of the material, and on the other hand the removal of superficially built up analysate.
Thus, when a process and a means are used which are described in detail in DE-A-
The invention allows the scrapers to move over a fixed tube. However, it is preferable to design the inner and outer scrapers as immovable and to move the focus tube up and down between the scrapers to accomplish the scraping in that fashion.
The scrapers form rings on the inner and outer focus tube wall. The vertical height of the scrapers can be selected In accordance with practical requirements. As the focus tube moves relative to the scrapers, the scrapers slide along the inner and outer wall of the focus tube in the bottom area, thus loosening particles of the analysate which build up on the measuring tube. To ensure the optimal functioning of the scrapers, they are preferably abutting the focus tube such that they do not dip into the horizontal stream of the analysate while measuring is being performed. On the other hand, the focus tube can also be cleaned while the scrapers are immersed due to the relative movement.
The particularly preferred movement of the focus tube relative to the fixed scrapers during the scraping process makes it possible to immerse the measuring tube into the continuing stream for another measurement, such that the salt composition on a conveyor belt is analyzed by the measuring position at time intervals.
During the measurement, the measuring tube sometimes penetrates the analysate so deeply that the bottom edge of the measuring tube is completely immersed in the analysate.
It has been proven to be advantageous to bevel the bottom end of the measuring tube such that the bottom edge of the measuring tube on the inflow side of the analysate stream immerses more deeply into the stream than on the oufflow side.
This prevents a stronger inflow of the analysate into the measuring tube and its rise inside the measuring tube.
The scraping movement can be driven in any suitable manner. Preferably, the measuring tube is provided with a pneumatic drive unit for the automatic relative movement of the focus tube relative to the scrapers.
It is also advantageous to provide a control unit to automate the scraping process.
The scraping movement can take place in regular variably adjustable time intervals during LIBS measurements in online mode.
Thus the LIBS measurement can be conducted in online mode while analysate building up on the measuring tube is scraped off, preferably automatically, by means of the movement of the focus tube relative to the scrapers.
According to a preferred embodiment, the measuring tube is provided with an inlet for receiving inert gas. This makes it possible to apply the LIBS analysis process under inert gas in online mode. This is necessary, for example, to determine sulfur in the UV range.
In these measurements it is preferred to fill the entire measuring tube with inert gas.
To prevent too much inert gas from escaping, the bottom edge of the measuring tube can be immersed completely in the analysate. However, as long as a sufficient stream of inert gas is provided, the bottom edge of the measuring tube can also lie partly or completely above the analysate as long as air or oxygen is prevented from entering in the area between the material surface and the top end of the measuring tube (inside).
Since the height of the poured analysate stream can vary, it is advantageous to provide an autofocus system in the online LIBS analysis unit that serves to adjust the measuring distance to the analysate.
The measuring tube according to the invention, the analysis unit according to the invention and the process according to the invention can be applied to any type of analysate: solid, gas, gel, sol, dispersion, liquid or mixtures thereof. A
preferred analysate is a salt, preferably a raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt.
In particular, the purpose of the process according to the invention is to determine the sulfur content of a salt in online mode under an inert gas atmosphere.
The LIBS analysis according to the invention can be performed as described in the introduction. Preferred designs of the measuring tube and the analysis unit are described below.
Preferably, the measuring system is provided with an automatic control and can signal the current state (such as standby, ready, measuring, error) to the superior process control system. In addition, self-testing is performed to ensure functional readiness.
The measuring system automatically performs measurements on moving material, for example on a conveyor belt.
During the examination of the material surface, the latter is subjected to laser radiation which induces the emission of plasma radiation. This is detected in an analysis optics and evaluated with the integrated signal electronics and control software.
The measuring system is designed to transmit the measuring results to a superior process control system.
Recalibration and test equipment monitoring is performed in predetermined time intervals.
All readings, test results and information regarding the system status are recorded.
The laser-based online measuring system and the continuous analysis allow a quasi real-time process control and process optimization.
Preferably, the analysis optics allows analysis in the spectral range from 170 to 590 nm and if need be also in the IR range. Using the LIBS process, the measuring system continuously examines the material, for example on a conveyor belt. The contents of the determined elements are available online to system users.
The measurement system consists of the following components: housing, laser source, optics including the measuring tube, autofocus system, electronic control system, software and protective devices.
The housing serves to accommodate all optical and electronic components and the media and user interfaces. Preferably, the housing, including cable entry, is protected against water jets, is dustproof, laser-proof and temperature-stabilized.
The measuring tube protects the optics against contamination and also allows the determination of elements under an inert gas atmosphere in the VUV range. The measuring tube is a part of the focusing optics and is flanged to the optic module which also includes the laser, optics and the spectrometer.
The laser used is a pulsed Nd:YAG laser source (laser class 4) with intermediate optical power of max. 30 W to excite the element-specific optical emissions.
An autofocus system serves to adjust the measuring distance, for example different layer thicknesses. It consists of distance sensors and traversing units which ensure the focusing of the laser beam upon the material surface.
The electronic control system serves to control the process.
The control software also serves to control the process, provides the connection to a process control system, to control and operate the measuring system, to evaluate the readings, calibration, recalibration, test equipment monitoring, interface to the process control computer, and also evaluates the log function, facility operation and remote maintenance.
In practice, preferably protective means are provided which protect against laser radiation and movable parts by means of an interlock circuit, safety locks, etc.
It is possible to guide the pulsed laser beam synchronous with movement with a preselected measuring point from the moved analysate such that successive laser pulses or laser bursts can be applied several times in a row upon the same sample point. This allows on the one hand an in-depth analysis of the material, and on the other hand the removal of superficially built up analysate.
Thus, when a process and a means are used which are described in detail in DE-A-
10 2008 032 532, it is possible by means of a pulsed laser beam to carry out a preparatory laser material ablation, even with moving measuring objects.
In principle it is also possible to carry out measurements at several measuring points within the measuring tube. Such a process is described, for example, in DE-A-2004 051 310.
It is also possible to carry out the LIBS measurement with a laser-induced fluorescence measurement (LIS measurement) as described, for example, in DE-A-2004 051 311.
to It is also possible to use double-pulsed laser systems which may be present in orthogonal or perpendicular configuration. For example, a signal amplification can be achieved in that way which would otherwise only be possible by working at reduced pressures.
is The present invention is described further by means of the following examples:
Example 1 The measuring tube was developed with the basic idea that it consists of a double tube system where the focus tube in the real-time online mode is to be operated by means of autofocus as close as possible above the salt surface for the required inert gas atmosphere, but with the least possible surface contact, or alternatively is to immerse into the salt. For a case when there is contact between the focus tube and the salt, a double tube with manual scraper (in online operation, scraping can be automated and clocked) inside the tube was designed for the basic tests. The outer tube represents the outer scraper. In the inner tube (which corresponds to the focus tube), another tube is provided as an inner scraper. Fig. 1 and 2 show a schematic view of the automated measuring tube based on the manual measuring tube as an exploded view with the following reference numbers:
1 Scraper, inside 2 Scraper, outside 3 Focus tube 4 Control and evaluation logic Fig. 3 shows a top view and a cross sectional view of the manual measuring tube with scrapers.
The manual measuring tube was installed vertically over a horizontal conveyor belt.
Salt was conveyed on the conveyor belt.
The manual measuring tube was first installed such that the extended focus tube was minimally above the salt surface. However, since the layer thickness was not constant, there quickly was contact between the focus tube and the salt.
Subsequently the focus tube was immersed more deeply to expose it to maximum conditions, and it was deliberately left in full contact with the salt. This was to examine whether there would be salt accumulation in the inside tube and whether the outside caking at the inside tube could be easily removed with the scraper mechanism provided. Several focus tube/salt contact periods were tested prior to manual operation of the scraper mechanism.
Several time intervals were tested (repeated 1 minute, repeated 5 minutes, 1 hour, 1.5 hours) between applications of the scraper mechanism.
Observations after repeated 1 minute contact between focus tube and salt (immersion time):
The outer part of the focus tube, which had been in direct contact with the product stream, showed a first build-up of salt. However, there was no caking and build-up of salt in the inner tube and at the inner tube edge. After the scraper mechanism was used, the outer build-up could be removed without a problem.
Observations after repeated 5 minute contact between focus tube and salt (immersion time):
The outer part of the focus tube that had contact with the product stream had new salt build-up. After that period, a first small caking of salt was seen at the inner tube edge. However, there still was no caking or salt build-up directly in the inner tube. In this case, too, the outer build-up and the build-up on the inner tube edge could be easily removed by operating the scraper mechanism.
Observations during a spontaneously occurring salt product blockage:
During the test phase there was a salt blockage on the conveyor belt, and for a short time no evaporated salt was moved on the belt.
When the blockage was cleared, there were great irregularities in the conveyance of salt. The height of the manual measuring tube was deliberately not changed but exposed to these difficult conditions to test its behaviour during such a product blockage. We observed that the focus tube was partly immersed in the product stream up to the outer scraper.
Apart from the irregular layer on the conveyor belt, there were some large salt clumps on the belt, but these were deflected from the measuring tube without problem and continued to be conveyed on the side of the belt without dropping from is the wet salt belt.
After deep immersion in the product stream and contact with the salt clumps, the measuring tube again showed caking outside on the edges and on the focus tube.
By operating the scraping mechanism, they could again be removed without a problem.
Observations after 1 and 1.5 hours of contact between focus tube and salt:
The outer part of the focus tube that had contact with the product stream had larger salt build-up, and salt caking was also visible on the edge of the inner tube.
However, these were not any larger than after the 5 minute contact, probably because some of the caking on the edges continued to come off by itself during movement in the conveying process. Directly in the inner tube there was no caking or salt build-up, neither after 1 hour nor after 1.5 hours. By operating the scraping mechanism after this lengthy contact, the outer build-up and the build-up at the inner tube edge could be removed. After we removed the measuring tube, we also saw that there was no caking at the bevelled rear part of the focus tube. Thus, the front focus tube part has functioned as a kind of plough and the bevelled rear tube geometry probably prevented salt build-up in the inner tube part.
Example 2 We found advantageous measuring tube behaviour in automatic operation in an automated measuring tube according to Fig. 1, comparable to that in Example 1.
In principle it is also possible to carry out measurements at several measuring points within the measuring tube. Such a process is described, for example, in DE-A-2004 051 310.
It is also possible to carry out the LIBS measurement with a laser-induced fluorescence measurement (LIS measurement) as described, for example, in DE-A-2004 051 311.
to It is also possible to use double-pulsed laser systems which may be present in orthogonal or perpendicular configuration. For example, a signal amplification can be achieved in that way which would otherwise only be possible by working at reduced pressures.
is The present invention is described further by means of the following examples:
Example 1 The measuring tube was developed with the basic idea that it consists of a double tube system where the focus tube in the real-time online mode is to be operated by means of autofocus as close as possible above the salt surface for the required inert gas atmosphere, but with the least possible surface contact, or alternatively is to immerse into the salt. For a case when there is contact between the focus tube and the salt, a double tube with manual scraper (in online operation, scraping can be automated and clocked) inside the tube was designed for the basic tests. The outer tube represents the outer scraper. In the inner tube (which corresponds to the focus tube), another tube is provided as an inner scraper. Fig. 1 and 2 show a schematic view of the automated measuring tube based on the manual measuring tube as an exploded view with the following reference numbers:
1 Scraper, inside 2 Scraper, outside 3 Focus tube 4 Control and evaluation logic Fig. 3 shows a top view and a cross sectional view of the manual measuring tube with scrapers.
The manual measuring tube was installed vertically over a horizontal conveyor belt.
Salt was conveyed on the conveyor belt.
The manual measuring tube was first installed such that the extended focus tube was minimally above the salt surface. However, since the layer thickness was not constant, there quickly was contact between the focus tube and the salt.
Subsequently the focus tube was immersed more deeply to expose it to maximum conditions, and it was deliberately left in full contact with the salt. This was to examine whether there would be salt accumulation in the inside tube and whether the outside caking at the inside tube could be easily removed with the scraper mechanism provided. Several focus tube/salt contact periods were tested prior to manual operation of the scraper mechanism.
Several time intervals were tested (repeated 1 minute, repeated 5 minutes, 1 hour, 1.5 hours) between applications of the scraper mechanism.
Observations after repeated 1 minute contact between focus tube and salt (immersion time):
The outer part of the focus tube, which had been in direct contact with the product stream, showed a first build-up of salt. However, there was no caking and build-up of salt in the inner tube and at the inner tube edge. After the scraper mechanism was used, the outer build-up could be removed without a problem.
Observations after repeated 5 minute contact between focus tube and salt (immersion time):
The outer part of the focus tube that had contact with the product stream had new salt build-up. After that period, a first small caking of salt was seen at the inner tube edge. However, there still was no caking or salt build-up directly in the inner tube. In this case, too, the outer build-up and the build-up on the inner tube edge could be easily removed by operating the scraper mechanism.
Observations during a spontaneously occurring salt product blockage:
During the test phase there was a salt blockage on the conveyor belt, and for a short time no evaporated salt was moved on the belt.
When the blockage was cleared, there were great irregularities in the conveyance of salt. The height of the manual measuring tube was deliberately not changed but exposed to these difficult conditions to test its behaviour during such a product blockage. We observed that the focus tube was partly immersed in the product stream up to the outer scraper.
Apart from the irregular layer on the conveyor belt, there were some large salt clumps on the belt, but these were deflected from the measuring tube without problem and continued to be conveyed on the side of the belt without dropping from is the wet salt belt.
After deep immersion in the product stream and contact with the salt clumps, the measuring tube again showed caking outside on the edges and on the focus tube.
By operating the scraping mechanism, they could again be removed without a problem.
Observations after 1 and 1.5 hours of contact between focus tube and salt:
The outer part of the focus tube that had contact with the product stream had larger salt build-up, and salt caking was also visible on the edge of the inner tube.
However, these were not any larger than after the 5 minute contact, probably because some of the caking on the edges continued to come off by itself during movement in the conveying process. Directly in the inner tube there was no caking or salt build-up, neither after 1 hour nor after 1.5 hours. By operating the scraping mechanism after this lengthy contact, the outer build-up and the build-up at the inner tube edge could be removed. After we removed the measuring tube, we also saw that there was no caking at the bevelled rear part of the focus tube. Thus, the front focus tube part has functioned as a kind of plough and the bevelled rear tube geometry probably prevented salt build-up in the inner tube part.
Example 2 We found advantageous measuring tube behaviour in automatic operation in an automated measuring tube according to Fig. 1, comparable to that in Example 1.
Claims (20)
1. LIBS measuring tube for the vertical immersion in an analysate moved in a horizontal stream, especially a loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, characterized in that the measuring tube extends vertically, is hollow on the inside and open at least at the bottom end such that a bottom edge forms at the bottom end, the measuring tube has at the top end an inlet for coupling a laser beam and an outlet for uncoupling an emission spectrum, the measuring tube is designed such that in the measuring tube the laser beam is focused upon the analysate, especially a loose bulk material, in particular raw, intermediate and end products from the processing of potassium, magnesium, rock salt or evaporated salt, such that inside the measuring tube, without additional scattering or deflection, a plasma of the analysate is formed by the laser radiation, and the emission spectrum of the analysate passes through the inside of the measuring tube to the outlet, that abutting at the inner and outer wall of the focus tube scraper rings are provided, preferably at the same vertical height on the focus tube, which are vertically movable against the focus tube such that analysate building up inside and outside the focus tube can be scraped off by moving the focus tube relative to the scrapers in the lower area.
2. Measuring tube according to Claim 1, characterized in that the measuring tube is provided with an inlet for feeding in inert gas which allows the detection of the spectra of elements emitting in the VUV range, preferably sulfur.
3. Measuring tube according to Claim 1 or 2, characterized in that the scrapers are abutting on the focus tube such that in operation they do not immerse in the horizontal stream of analysate.
4. Measuring tube according to Claims 1 to 3, characterized in that the focus tube and the scrapers are annular in shape.
5. Measuring tube according to one of Claims 1 to 4, characterized in that the focus tube and the scrapers are circular in cross section.
6. Measuring tube according to one of Claims 1 to 5, characterized in that the bottom end of the measuring tube is bevelled such that the bottom edge of the measuring tube immerses more deeply into the analysate stream on the inflow side than on the outflow side.
7. Measuring tube according to one of Claims 1 to 6, characterized in that it is provided with a preferably pneumatic drive unit for automatic movement of the focus tube relative to the scrapers.
8. Online LIBS analysis unit comprising a LIBS measuring tube according to one of Claims 1 to 7, a laser source, a spectrometer unit for detecting the LIBS emission spectrum, with analysis optics for the spectral range of 170-590 nm and if need be for detecting in the IR
range, optical components for coupling the laser beam into the measuring tube and uncoupling the emission spectrum from the measuring tube, an electronic control for operating the laser source and the detector unit, and for recording the readings, a preferably pneumatic drive unit for automatically moving the focus tube relative to the scrapers, a means for feeding inert gas into the measuring tube to allow the detection of spectra of the elements emitting in the VUV range, preferably sulfur.
range, optical components for coupling the laser beam into the measuring tube and uncoupling the emission spectrum from the measuring tube, an electronic control for operating the laser source and the detector unit, and for recording the readings, a preferably pneumatic drive unit for automatically moving the focus tube relative to the scrapers, a means for feeding inert gas into the measuring tube to allow the detection of spectra of the elements emitting in the VUV range, preferably sulfur.
9. Analysis unit according to Claim 8, also comprising an autofocus system for adjusting the measuring distance to the analysate.
10. Analysis unit according to Claim 8 or 9, also comprising a control unit for automating the scraping operation by means of a preferably pneumatic drive unit for the movement of the focus tube relative to the scrapers.
11. Application of a measuring tube according to one of Claims 1 to 7 or an online LIBS analysis unit according to one of Claims 8 to 10 for the qualitative and/or quantitative online determination of individual or multiple chemical elements of an analysate being moved past the measuring tube in a horizontal stream.
12. Application according to Claim 11, characterized in that the analysate is a solid, preferably a loose bulk material, a gas, sol, dispersion, liquid or mixtures thereof.
13. Application according to Claims 11 or 12, characterized in that the analysate is a salt, preferably a raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt.
14. Application according to Claim 13, characterized in that especially the sulfur content of salt is determined in online operation under an inert gas atmosphere.
15. Process for the qualitative and/or quantitative online determination of individual or multiple elements of an analysate, in particular raw, intermediate or end products from the processing of potassium, magnesium, rock salt or evaporated salt being moved in a horizontal stream, with an online LIBS analysis unit according to one of Claims 8 to 10, whereby the LIBS measuring tube is vertically immersed in an analysate that is moved in a horizontal stream, a LIBS laser beam is generated from a laser source and inside the measuring tube focussed upon the analysate, such that a plasma of the analysate is formed by the laser radiation inside the measuring tube, and the emission spectrum of the analysate is moved inside the measuring tube to the outlet to be uncoupled in the detector unit where the measured values are acquired.
16. Process according to Claim 15, characterized in that the LIBS
measurements are conducted in succession online, whereby analysate building up on the measuring tube during LIBS measuring is scraped off, preferably automatically, by moving the focus tube relative to the scrapers.
measurements are conducted in succession online, whereby analysate building up on the measuring tube during LIBS measuring is scraped off, preferably automatically, by moving the focus tube relative to the scrapers.
17. Process according to Claim 15 or 16, characterized in that the LIBS
measuring is conducted under an inert gas atmosphere by inert gas being fed into the measuring tube.
measuring is conducted under an inert gas atmosphere by inert gas being fed into the measuring tube.
18. Process according to one of Claims 15 to 17, characterized in that the analysate is a solid, especially a loose bulk material, or a gas, gel, sol, dispersion, liquid or mixtures thereof.
19. Process according to one of Claims 15 to 18, characterized in that the analysate is preferably a salt, preferably loose bulk material, in particular a raw, intermediate or end product from the processing of potassium, magnesium, rock salt or evaporated salt.
20. Process according to Claim 19, characterized in that in particular the sulfur content of the salt is determined online under an inert gas.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102013009962.5A DE102013009962B3 (en) | 2013-06-14 | 2013-06-14 | LIBS viewing tube |
| DE102013009962.5 | 2013-06-14 | ||
| PCT/DE2014/000300 WO2014198256A1 (en) | 2013-06-14 | 2014-06-12 | Libs measurement tube |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2915399A1 true CA2915399A1 (en) | 2014-12-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2915399A Abandoned CA2915399A1 (en) | 2013-06-14 | 2014-06-12 | Libs measuring tube |
Country Status (6)
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| US (1) | US9625391B2 (en) |
| EP (1) | EP3008434B1 (en) |
| CN (1) | CN105431719B (en) |
| CA (1) | CA2915399A1 (en) |
| DE (1) | DE102013009962B3 (en) |
| WO (1) | WO2014198256A1 (en) |
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| CN105203526B (en) * | 2015-09-22 | 2017-08-25 | 中国科学院上海技术物理研究所 | Exempt from the remote quantitative LIBS analysis method of calibration |
| FR3088432B1 (en) * | 2018-11-14 | 2020-12-11 | Commissariat Energie Atomique | DEVICE FOR CHARACTERIZING A LIQUID MATERIAL |
| CN111413325A (en) * | 2020-04-13 | 2020-07-14 | 中国海洋大学 | Method for improving measurement accuracy of rugged sample elements based on L IBS |
| CN112255149B (en) * | 2020-10-10 | 2022-07-05 | 中国科学院近代物理研究所 | Method and system for detecting particle size of loose particle accumulation and storage medium |
| DE202022104717U1 (en) | 2022-08-19 | 2023-11-22 | Hydro Aluminium Recycling Deutschland Gmbh | System for analyzing and sorting a piece of material |
| CN117589750A (en) * | 2024-01-18 | 2024-02-23 | 山东智谷碳素研究院有限公司 | Petroleum coke component analysis and detection device based on LIBS technology |
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| GB8403976D0 (en) * | 1984-02-15 | 1984-03-21 | British Steel Corp | Analysis of materials |
| DE58908876D1 (en) * | 1988-10-03 | 1995-02-23 | Krupp Ag Hoesch Krupp | Method for the optical coupling of an element analysis system and a laser to liquid metal in a melting vessel. |
| DE4004627C2 (en) * | 1990-02-15 | 1994-03-31 | Krupp Ag Hoesch Krupp | Method for determining material properties of polymer materials and device for carrying out the method |
| GB9005021D0 (en) * | 1990-03-06 | 1990-05-02 | Alfa Laval Sharples Ltd | Turbidity measurement |
| DE4102767A1 (en) * | 1991-01-31 | 1992-08-06 | Metallgesellschaft Ag | METHOD FOR QUALITATIVE ANALYSIS OF PLASTIC PARTICLES |
| JP2870364B2 (en) | 1993-06-29 | 1999-03-17 | 日本鋼管株式会社 | Laser vaporization analysis method and apparatus |
| DE69327463T2 (en) * | 1993-08-13 | 2000-07-20 | Pirelli | Method and device for determining the carbon black content of rubber compounds |
| DE4443407C2 (en) * | 1993-12-08 | 1999-07-22 | Fraunhofer Ges Forschung | Device for the qualitative and / or quantitative chemical analysis of a substance, in particular for the analysis of a molten metal |
| US6762835B2 (en) * | 2002-03-18 | 2004-07-13 | Mississippi State University | Fiber optic laser-induced breakdown spectroscopy sensor for molten material analysis |
| US6784429B2 (en) * | 2002-04-19 | 2004-08-31 | Energy Research Company | Apparatus and method for in situ, real time measurements of properties of liquids |
| AU2004299940C1 (en) | 2003-12-17 | 2009-05-14 | Heraeus Electro-Nite International N.V. | Method for analysis of a fused material device and dipping sensor |
| DE10359447B4 (en) * | 2003-12-17 | 2006-03-30 | Heraeus Electro-Nite International N.V. | Immersion sensor |
| DE102004051311B9 (en) | 2004-10-21 | 2008-12-04 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Apparatus and method for performing fluorescence and emission spectrometry |
| DE102004051310B4 (en) | 2004-10-21 | 2010-06-02 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Apparatus and method for performing emission spectrometry |
| DE202005011177U1 (en) * | 2005-07-15 | 2006-11-23 | J & M Analytische Mess- Und Regeltechnik Gmbh | Device for analysis, in particular photometric or spectrophotometric analysis |
| DE102006013341B3 (en) * | 2006-03-23 | 2007-10-18 | J & M Analytische Mess- Und Regeltechnik Gmbh | Apparatus and method for analysis, in particular photometric or spectrophotometric analysis |
| AT503539B1 (en) * | 2006-05-09 | 2008-03-15 | Innsitec Laser Technologies Gm | DIVE PROBE FOR LIPS DEVICES |
| DE102007016612A1 (en) * | 2007-04-05 | 2008-10-09 | BAM Bundesanstalt für Materialforschung und -prüfung | Apparatus and method for assaying a heterogeneous material by laser-induced plasma spectroscopy |
| DE102008032532B4 (en) | 2008-07-10 | 2023-10-26 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method and device for preparatory laser material removal |
| DE102009028254A1 (en) | 2009-04-22 | 2010-10-28 | Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG | Method for investigations on liquids and device therefor |
| US8902422B2 (en) * | 2011-10-21 | 2014-12-02 | Chesner Engineering, Pc | Bulk material sampling and laser targeting system |
| CN102590157B (en) * | 2012-02-20 | 2014-04-09 | 山西大学 | Element spectrum analysis method and laser element exploration equipment adopting same |
| CN102608080A (en) * | 2012-03-06 | 2012-07-25 | 唐山赛福特电子信息工程有限公司 | LIBS (laser induced breakdown spectroscopy)-based molten steel ingredient real-time and online detection system |
| CN102661935A (en) * | 2012-05-15 | 2012-09-12 | 广东电网公司电力科学研究院 | LIBS (Laser-induced Breakdown Spectroscopy) belt type powdery material detector |
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| US9625391B2 (en) | 2017-04-18 |
| EP3008434B1 (en) | 2017-08-02 |
| WO2014198256A1 (en) | 2014-12-18 |
| DE102013009962B3 (en) | 2014-11-06 |
| EP3008434A1 (en) | 2016-04-20 |
| CN105431719A (en) | 2016-03-23 |
| CN105431719B (en) | 2018-08-21 |
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